package com.hmdp.service.impl;

import cn.hutool.core.lang.UUID;
import com.hmdp.service.ILock;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;


import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {

    private String name;

    private StringRedisTemplate stringRedisTemplate;

    private static final String KEY_PREFIX="lock:";
    private static final String ID_PREFIX= UUID.randomUUID().toString(true)+"-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryLock(Long timeout) {
        //获取线程标识
        String threadId = ID_PREFIX+Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name, threadId, timeout, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock() {
        //调用lua脚本,满足原子性
        stringRedisTemplate.execute(UNLOCK_SCRIPT, Collections.singletonList(KEY_PREFIX+name),ID_PREFIX+Thread.currentThread().getId());
    }

    //@Override
    //public void unlock() {
    //    //获取线程标识
    //    String threadId = ID_PREFIX+Thread.currentThread().getId();
    //    String redisThreadId = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
    //    if (threadId.equals(redisThreadId)){
    //        //释放锁
    //        stringRedisTemplate.delete(KEY_PREFIX+name);
    //    }
    //
    //}
}
